As disclosed in Sterling Drug's U.S. Pat. Nos. 3,753,993 (Lesher et al.), 3,907,808 (Lesher and Carabateas), and 4,118,557 (Lesher), it is known that antibacterial 1-alkyl-1,4-dihydro-4-oxo-7-pyridinyl-3-quinolinecarboxylic acids can be prepared from 4-(3-aminophenyl)pyridine. It is also known that this route to the bactericides, as disclosed, is less economical than might be desired.
From Mitscher et al., "Quinoline Antimicrobial Agents. 1. Versatile New Synthesis of 1-Alkyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic Acids," Journal of Medicinal Chemistry, 1978, Vol. 21, No. 5, pp. 485-489, it is also known that antimicrobial agents related to the aforementioned bactericides can be prepared from the appropriate isatoic anhydrides.
It would be desirable to be able to prepare the antibacterial agents of Lesher, Lesher et al, and Lesher and Carabateas by a route similar to that employed by Mitscher et al; and 4-(4-alkyl-3-nitrophenyl)pyridines, as well as 2-nitro- and 2-amino-4-(4-pyridinyl)benzoic acids, that are useful in this regard are disclosed in (1) copending application Ser. No. 511,887, filed July 8, 1983, in the name of Thomas J. Walter (Walter), (2) copending application Ser. No. 511,854, filed July 8, 1983, in the name of V. Ramachandran (Ramachandran), and (3) copending application Ser. No. 511,844, filed July 8, 1983, in the names of Paul F. Ranken and Thomas J. Walter (Ranken and Walter).
Organic Syntheses, Collective Volume 3, pages 488-490, teaches that isatoic anhydrides can be prepared by treating an aqueous solution of the hydrochloride salt of an anthranilic acid with gaseous phosgene.